The present invention relates to computers, methods and computer program products wherein destination email addresses are checked against historical email address information to prevent an email from being sent to an unintended recipient.
With the rapid progress of Internet technology, information has been frequently exchanged using emails. Upon receiving an email, the recipient may respond by creating an email that includes historical information regarding other emails previously exchanged between multiple users, including the received email. An email containing historical information may include a header containing a destination email address, a body containing the message to be sent, and a historical information section citing emails exchanged between multiple users. In the case where multiple users have exchanged emails containing historical information with each other several times, this historical information section may become enormous, making it difficult for the user to check and grasp all the historical information. For this reason, when sending an email containing historical information, the user may send the email to an unintended destination, to which the sender does not want to disclose the historical information.
In view of the foregoing, numerous email sending methods have been developed to prevent the user from sending an email to an unintended destination. For example, a user terminal disclosed in Japanese Published Unexamined Patent Application No. 2007-193717 (“Patent Document 1”) includes an address book that stores email addresses and identification data such as the names, prefixes, company names, section names, job titles, postal addresses, and photos or illustrations of the owners of the email addresses. Each email address is associated with corresponding identification data and send/receive history data, such as the send/receive frequencies of previous emails and the send/receive dates and times. Before sending an email, the user terminal checks the data to be sent, which contains a destination email address, a destination name, an email body and the like, against the address book and the send/receive history file, so as to extract identification data and send/receive history data corresponding to the destination email address to give a warning to the user if necessary.
While the email sending method disclosed in Patent Document 1 includes determining whether a destination email address is stored in the address book, it does not include determining whether the destination email address is an intended destination to which the user is permitted to disclose the historical information section of the email. Accordingly, as long as the unintended destination is an email address stored in the address book, the email containing the historical information may be sent to unintended destinations to which the user does not need or want to disclose the historical information. This presents the problem of indiscriminately disclosing historical information.
For example, assume that a user “A” has exchanged emails containing historical information on several occasions with a user B (in the company) and a user C (outside the company), whose email addresses are stored in the address book and that, in reply to a received email, the user A sends an email containing historical information that cites the received email. If the user A selects a user D (outside the company), whose email address is stored in the address book, as the reply destination and attempts to send the email containing the historical information thereto, the email sending method disclosed in Patent Document 1 will send the email to the user D. This is because the user D is stored in the address book and is therefore handled as users B and C are handled. As a result, disadvantageously, the contents of the email containing the historical information that user A has several times exchanged emails with users B and C will leak to user D, failing to maintain confidentiality.